import React, { Component } from "react";
import "./index.css"

export default class Footer extends Component {

  handleCheckAll = (event) => {
    this.props.checkAllTodo (event.target.checked)
  }

  handleClearAllDone = () => {
    this.props.clearAllDone ()
  }

  render() {
    const {todos} = this.props
    // 已完成
    const doneCount = todos.reduce ((pre, todoObj) => {return pre + (todoObj.done? 1: 0)}, 0)
    // 总数
    const total = todos.length
    return (
      <div className="todo-footer">
        <label>
          <input type="checkbox"  onChange={this.handleCheckAll} checked={doneCount === total && total !== 0? true: false}/>
        </label>
        <span>
          <span>已完成{doneCount}</span> / 全部{total}
        </span>
        <button className="btn btn-danger" onClick={this.handleClearAllDone}>清除已完成任务</button>
      </div>
    )
  }
}